Common juniper is possibly the most widely distributed tree in the world. Common juniper is highly valued as an ornamental, provides good ground cover even on stony or sandy sites. This species was first cultivated in 1560. This circumboreal species occurs across North America, Europe, northern Asia and Japan. Common juniper is almost completely circumpolar within the exception of a gap in the Bering Sea region. It is widespread in North America beyond the northern limit of trees, occurring from western Alaska and British Columbia to Newfoundland, Greenland, and Iceland. Common juniper extends southward through New England to the Carolinas and westward through northeastern Illinois, Indiana, northern Ohio, Minnesota, and Nebraska to the western mountains of Washington, California, Arizona, and New Mexico.

This Swedish Juniper at the Morton Arboretum is 47 years old. Grows best in full sun.

Common juniper is a native, evergreen shrub or columnar tree. Throughout most of North America, common juniper most often grows as a low, decumbent mat-forming shrub reaching up to 4.9 feet (1.5 m) in height and 7.6 to 13.1 feet (2-4 m) across. In parts of New England common juniper occasionally grows up to 25 feet (7.6 m) in height, and a treelike growth form is reportedly common in Europe. Height at maturity can range from 2 to 50 feet (0.6-15.3 m). At polar limits, common juniper grows as a dwarf shrub in forest tundra.

The bark of common juniper is thin, shreddy or scaly, often exfoliating into thin strips. Twigs tend to be yellowish or green when young but turn brown and harden with age. Leaves are simple, stiff and arranged in whorls of 3. Younger leaves tend to be more needlelike whereas mature leaves are scalelike. Male strobili are sessile or stalked, and female strobili are made up of green, ovate or acuminate scales. Berrylike cones are red at first, ripening to a glaucous bluish-black.

The bark of common juniper is thin, shreddy or scaly, often exfoliating into thin strips.

Domestic livestock rarely utilize common juniper. The foliage may be poisonous to domestic goats, although livestock in parts of Europe have reportedly been fed sprays of common juniper with no ill effects. Cones of most junipers are eaten by many species of birds and mammals. Numerous animals, including the American robin and black-capped chickadee, feed on the cones of common juniper whenever they are available. American robins frequently consume large numbers of cones during the spring and fall. In eastern Ontario, cones provide food for cedar and Bohemian waxwings. Wild turkeys also feed on cones of common juniper.

The shade and cover value of common juniper tends to be greatest for birds and small mammals. It provides especially good nesting cover for Merriam's wild turkeys in the Black Hills of South Dakota. In New Jersey, it provides winter roosts for short-eared owls. In the Northwest Territories, common juniper branches are used in woodrat nests.

Common juniper was used by Native Americans of the Great Basin as a blood tonic. Native Americans from the Pacific Northwest used tonics made from the branches to treat colds, flu, arthritis, muscle aches, and kidney problems. Cones were used by the southern Kwakiutl of British Columbia for treating stomach ailments and wood or bark was used to treat respiratory problems. The Interior Salish used cones to make medicines for a variety of ailments. Eurasians made tonics from common juniper for kidney and stomach ailments, and rheumatism. Common juniper contains a volatile oil, terpinen-4-ol, which is known to increase kidney action [130]. Common juniper extract, which can be fatal in even fairly small amounts, was used to make gin and as a meat preservative.